FML
Clinical safety rating: caution
Comprehensive clinical and safety monograph for FML (FML).
Agonist at glucocorticoid receptors, leading to inhibition of phospholipase A2 via annexin-1 induction, reducing prostaglandin and leukotriene synthesis; also suppresses cytokine production and inflammatory cell migration.
| Metabolism | Primarily hepatic via CYP3A4; undergoes reduction and conjugation to inactive metabolites. |
| Excretion | FML (fluorometholone) is primarily metabolized in the liver, with metabolites excreted renally. Approximately 70-80% of the dose is eliminated in urine as metabolites, with less than 5% as unchanged drug. Fecal excretion accounts for about 10%. |
| Half-life | The terminal elimination half-life of fluorometholone is approximately 1.5 hours in plasma. Clinically, this short half-life allows for multiple daily dosing; however, ocular administration results in sustained local effects due to corneal binding. |
| Protein binding | Plasma protein binding of fluorometholone is approximately 79-85%, primarily to albumin and corticosteroid-binding globulin. |
| Volume of Distribution | The volume of distribution (Vd) is approximately 1.0 L/kg, indicating extensive tissue distribution. This is consistent with its lipophilic nature, allowing penetration into ocular tissues. |
| Bioavailability | Ophthalmic suspension: Systemic bioavailability is extremely low (less than 1%) due to extensive first-pass metabolism in the eye and systemic circulation. Oral bioavailability is not clinically relevant as the drug is only administered topically. |
| Onset of Action | Ophthalmic suspension: Onset of action is within 1-2 hours after topical application, with maximal effect typically seen at 4-8 hours. |
| Duration of Action | Ophthalmic: Duration of anti-inflammatory effect is approximately 8-24 hours, depending on dosing frequency (typically 2-4 times daily). Systemic effects are limited due to low bioavailability. |
Fluorometholone ophthalmic suspension 0.1%: Instill 1 drop into conjunctival sac 2-4 times daily. In severe conditions, may increase to 1 drop every hour initially.
| Dosage form | SUSPENSION/DROPS |
| Renal impairment | No adjustment required. |
| Liver impairment | No adjustment required. |
| Pediatric use | Safety and efficacy in pediatric patients have not been established; use only if clearly needed. |
| Geriatric use | No specific dosage adjustment; use lowest effective dose for shortest duration due to increased risk of intraocular pressure elevation. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for FML (FML).
| Breastfeeding | Excreted in human milk in small amounts (M/P ratio unknown). Single maternal topical ocular doses unlikely to affect infant, but prolonged high-dose systemic therapy should be used cautiously due to potential for adrenal suppression or growth suppression in nursing infants. |
| Teratogenic Risk | Pregnancy Category C. In first trimester, possible increased risk of oral clefts (case-control studies inconsistent). Second/third trimester: chronic use may cause intrauterine growth restriction, adrenal suppression in fetus; avoid prolonged high-dose use. Systemic absorption from topical ophthalmic administration is low but can accumulate with extensive use. |
■ FDA Black Box Warning
None
| Common Effects | Eye irritation Burning sensation Watery eyes |
| Serious Effects |
["Untreated bacterial, fungal, or viral ocular infections (e.g., herpes simplex keratitis)","Hypersensitivity to fluorometholone or any component","Corneal epithelial defects (relative)"]
| Precautions | ["Prolonged use may cause elevated intraocular pressure, glaucoma, cataract formation, and secondary ocular infections.","May suppress immune response, increasing risk of fungal, viral, or bacterial infections.","Use with caution in patients with corneal thinning or epithelial defects.","Systemic absorption may occur with extensive topical use.","Not for use in patients with untreated ocular infections."] |
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| Fetal Monitoring | Monitor for intrauterine growth restriction (serial ultrasound if chronic use). Assess maternal adrenal suppression (ACTH stimulation test if high-dose systemic exposure). Monitor infant for signs of adrenal suppression if maternal long-term therapy near term. |
| Fertility Effects | No specific human data. In animal studies, corticosteroids may impair fertility at high doses (e.g., delayed ovulation, reduced implantation); relevance to ophthalmic use is minimal due to low systemic absorption. |